The Ability of Chlorophyll to Trap Carcinogen Aflatoxin B1: A Theoretical Approach

Abstract

The coordination of one and two aflatoxin B1 (AFB1, a potent carcinogen) molecules with chlorophyll a (chl a) was studied at a theoretical level. Calculations were performed using the M06-2X method in conjunction with the 6-311G(d,p) basis set, in both gas and water phases. The molecular electrostatic potential map shows the chemical activity of various sites of the AFB1 and chl a molecules. The energy difference between molecular orbitals of AFB1 and chl a allowed for the establishment of an intermolecular interaction. A charge transfer from AFB1 to the central cation of chl a was shown. The energies of the optimized structures for chl a show two configurations, unfolded and folded, with a difference of 15.41 kcal/mol. Chl a appeared axially coordinated to the plane (α-down or β-up) of the porphyrin moiety, either with the oxygen atom of the ketonic group, or with the oxygen atom of the lactone moiety of AFB1. The complexes of maximum stability were chl a 1-α-E-AFB1 and chl a 2-β-E-AFB1, at −36.4 and −39.2 kcal/mol, respectively. Additionally, with two AFB1 molecules were chl a 1-D-2AFB1 and chl a 2-E-2AFB1, at −60.0 and −64.8 kcal/mol, respectively. Finally, biosorbents containing chlorophyll could improve AFB1 adsorption.

Humic Acids Preparation, Characterization, and Their Potential Adsorption Capacity for Aflatoxin B1 in an In Vitro Poultry Digestive Model

“…For example, physical modelling (Langmuir isotherm), kinetic modelling (Elovich kinetic model), surface complexation modelling, and Ligand and charge distribution model, among others [ 54 ]. However, to elucidate the nature of the molecular interactions between HA and AFB 1 , future theoretical simulations using density functional theory (DFT) may be considered [ 56 ].…”

Computational Studies of Aflatoxin B1 (AFB1): A Review

“…(v). A quantitative description of the chemical interactions among one and two AFB 1 molecules with chlorophyll a (chl a) was obtained by Vázquez-Durán et al [ 33 ], using the M06-2X functional with the 6-311G(d,p) basis set, considering the gas and water phases. In this sense, molecular properties such as the molecular electrostatic potential surface, HOMO and LUMO, and charges were employed to characterize and describe the interaction sites.…”

“…As a part of our research program, in CC, we have performed valuable studies contributing to knowledge of the chemical behavior of AFB 1 . This information can be conveniently summarized as follows: (a) a mass spectrometry/mass spectrometry study on the degradation of AFB 1 in the maize with aqueous citric acid [ 28 ]; (b) theoretical calculations to confirm that the active site corresponds to the lactonic ring [ 29 ]; (c) a theoretical study [ 30 ] of 8-chloro-9-hydroxy-AFB 1 , which determined the structural, electronic, and spectroscopic properties of this reaction product of AFB 1 ; (d) a theoretical study [ 31 ] related to the adsorption process of B-aflatoxins using a vegetable specimen Pyracantha koidzumii (Hayata); (e) in a recent publication [ 32 ], the effectiveness of lettuce and field horsetail as biosorbents for the elimination of aflatoxin AFB 1 ; was evaluated (f) concluding with a recent in silico work [ 33 ], describing the interaction of chlorophyll with AFB 1 .…”